yes correct, Dharma Protectors 护法神 will protect those who practise the Dharma (note that the holy books of other religions are also considered the Dharma by the Buddhas), so we dont really need material things for protection, moreover amulets things were never taught by the Buddha.

but we also cannot simply write off the power of amulets, a lot of people were unharmed in car accident and found their amulet broken into half or shattered inside the cover, i have a friend he visited Sydney Old Town, he took a picture of himself in an old head-chopping board, when he came back his amulet broke into half exactly at the head of the Buddha.